Assioitob



B. W JONES.

MOTOR CONTROL SYSTEM APPLICATION FILED FEB. 4. 1918.

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5 wk B UNITED STATES PATENT o BENJAMIN To all whom it may concern Be it known that I, BE J MIn Jomzs, a citizen of the United States, residin at Schenectady, county of Schenectady, tate of New York, have invented certain new and useful Im rovements in Motor-Control Systems, specification.

, My invention relatesto motor control and has for its object an im roved system of starting and stopping an generally effectin the control of an electricmotor.

ore specifically my invention relates to the control of series motors intended for case of a reversing equipment where thereversals are frequent and hence the dynamic braking action -must efl'ect a quick stop vfrom elther direction of rotation. In carrying out my invention provide means whereby the directionof current through the field windings of the motor is always maintained while the'direction of current through the armature is reversed. In one,

form of my invention I provide an arrangement whereby when the controller is thrown to the ofi' or neutral position, the reverse connections of the armature are made and a dynamic brakin circuit established, while the polarity of t e field remainsunchanged. In other words, at the ofi positionof the controller, the armature connections will depend upon the direction in whichthe controller was last moved. If, for instance, the controller is moved to the. off. osition from a forward position the reverse connections of the armature will be established, and likewise, if the controller is moved to the off position from the reverse position, the forward connections of the armature will beestablished. The'flow of current through the field windv ing is, however, always in the same direction. In order to insure thatthe field shall a build up quickly, I maintain a connection between the field and line during the braking period but insert ahigh resistance in the connection so as not to affect the operation during braking. The result is that an effective braking action is obtained in the Specification of m... Intent.

" Application filed February 4, 1915. semi No. 215,300.

which the following is a Patented Sept. 9,1919.

ofi osition of the controller regardless of the lrection in which the armature was rotating.

For. a. more exact understanding of the nature and objects of this invention referdescription.- when taken in connection with the accompanying drawing in which Figure 1 shows, in diagrammatic fashion, a system of motor control embod ing my invention, while Fig. 2 is a simpli ed diagram ofthe motor connection shown in Fig. 1.

Referri and F denotes its field. The connections of the armature with the field are made by the electromagnetic switches or contactors B,, B,', B, and B These contactors are provided with interlocking means which permits but two to be closed at one time; that means comprising the pivoted. bars an l1,v the bar 10 cooperating with the upper ends of theplungers of contactors B and B,, the bar 11 cooperating with the contactors B, and B y The motor circuit is also provided with the accelerating contactors D D and'D which are arranged to successively short circuit the resistances R R, and R, cutting them out of the motorcircuit.

All of these contactors are arranged to be under the controlof the master switch or controllerO; as are also the braking relays and the runnin relays K and L. The braking relays and H are connected in the operating circuits betweenthe controller C and the contactors B B B and B so that, when the controller 18 mov from either running osition to the off or stopped position, t e connections of the armature A with the field F are reversed and the motor automatically becomes a mm; Jonas; or scnmmcramr, mew Yonx, assren'on r0 em unc'mro comm, a conrona'non or new YORK.

I I moron-common stem now to the drawing, A denotes the armature of the motor to be controlled,

so ence should be. had to the following detailed shownbeing a mechanical interlocking one comprisin the pivoted bar 13'co6perat-- ing with the p unrs of the relays. he unning re ays K and L are under the direct control of 'the controlle'r C. The relay K is arranged to complete a local circuit, here shown as a connection to und in parallel .with the armature A and field F .WhlCh includes the resistance P, for converting the motor into a braking generator.

out of the motor circuit when in service operation. This arrangement requires that relay L shall be energized while the con troller is in either forward or reverse POSI- tion, and that relay H or relay G (depending upon which way the controller has been moved) shall be energized while the controller is in neutral position, the line switch S being closed to supply the energizing current.

I have also provided relays K and L with interlocking means, here shown as a mechanical interlock comprising the pivoted bar 14 cooperating with the plungers of these relays.

The local circuit of the braking generator is here shown as provided with an accelerating contactor D to short circuit the resistance 1" out of the local circuit when the current of the braking generator ha attained sufficient strength, but obviously the use of an accelerating eontactor in the local circuit of the braking generator is not required in the practice of my invention.

The mode of operation of my invention is as follows Assuming that switch S has been closed and the controller C makes contact along the right-hand row of segments, current would then flow from the line E through the controller-and the conductor 15 to energize the relay L for short circuiting the resistance R, thence the current flows to ground. Current would also flow from the lineE through the controller and conductors 16 and 16 to energize the parallel controlled contactors B and B for completing the motor circuit, and thence the current flows to ground.

en the motor circuit has been completed by the closin of contactors B and B current will flow lrom the line E through resistance R and R by way of conductor 19, then successively through the winding of switch D, resistance R, thence to the field F, the armature A, and finally to ground by way of contactors B and B The accelerating contactors D D and D will now be successively energized to cut out the resistances R R and R respectively in a well known manner, thereby permitting the motor to accelerate to full load running condition.

In addition to the currents flowing through the controller C by way of conductors 15 and 16, current will also flow through the controller by way of conductor 17, conductor 18 being dead in this position of the .controller. The. current in conductor 17' will energize relay G for closing a circuit preparatory to the dynamic braking operation.

Assuming now that it is desired to stop the motor, the controller C would be moved to the oil position which corresponds with that shown in the drawing. In this position relay L is dener ized, current now flowing from the line L through the controller and conductor 20 to energize relay K for completing the local circuit of the braking generator, and thence this current flows to ground. In the off position conductor 18 is put in conducting relation with the line E, so that current now traverses it, flowing thence to conductor 21 by way of the switch previously closed by relay G. From conductor 21 the current energizes the parallel controlled contactors B and B,

and then flows to ground.

As soon as contactors B and B open, the cont-actors B and' B may close, thus connecting the motor throu h a local circuit including the field F anc the resistances r and I to convert the motor into a braking generator.

The resistance R having been inserted in the motor circuit by the o ening of relay L, 1t is seen that a relative y small current Wlll now flow from the line E through the field F and thence to ground, thereby insuring the same polarity to the field that it had when the dynamo machine was running as a motor. he counter E. M. F. will accordingly build up in the same direction as when the dynamo machine was a motor, which counter E. M. F. will cause a current to flow producing a counter torque that will brake the motor.

The armature and field connections having been reversed this counter current now flowmg 1n the local circuit will not interfere with the field excitation, but will assist it, thereby producing an increased braking effeet which quickly brings the motor to rest.

The accelerating contactor D will short c1rcu1t resistance r out of the local circuit in the usual manner, permitting .the counter current further to increase and apply still more counter torque thereby producing a powerful .braking effect without an initial rush of counter current which would produce only a heating effect.

When the controller 0 is subsegtuently moved to makecontact along the le hand row of contracts, current would flow from line E to energize relay L for short circuiting resistance R in the same manner as above described, the movement of the controller deenergizing the relay K. The holding circuit for the relay G including conductor 17 is also deenergized by this movement of the controller. Relay G consequently drops open and completes a hold'n circuit for relay H, permitting current to 50w from the line E through the controller and conductor 18 to energize relay H preparatory to anotherbraking operation; thence this current flows to ground.

It is now seen that a motor circuit is established from the line E about resistance R by way of conductor 19 for running the motor in service operation as before described, but in a reversed direction.

While I have here shown an embodiment of my invention which is, at present, thebest,

means known to me for carrying the same into effect, I would have it understood that this is merely illustrative and that I do not mean to be limited thereby to the precise.

details here disclosed since obvious alterations thereof will appear to those skilled in bination with a series motor and a controller for reversing the same, of means whereby a dynamic braking circuit is established and the direction of the current through the field winding is maintained when the controller is moved from either positionto the voff position.

2. In a system of motor control, the combination with a series motor and a controller for reversing the same, of means whereby when the controller ismoved from either position to the other position a dynamic braking circuit is established and the direction of the current through the field windings maintained in passing through the neutral position.

3. In a system of motor control, the com bination with a series motor and electromagnetic reversing switches therefor, of a reversing master controller'for said switches, and means whereby when the master con troller is moved from one operative position to the off position the reversing switches for the opposite direction of rotation will be closed and a dynamic braking circuit established with the direction of current through the field windings maintained.

4. In a system of motor control, the combination with a series motor and a controller for reversing thesame, ofmeans whereby when the controller is moved from either position to the oil position the armature connections are reversed with reference to those established when the controller is moved from the other position and a dynamic braking circuit established with the direction of current through thefield windings maintained. a

5. In a system of motor control, the combination with a dynamo-electric machine having an armature and series field, revers- -ing means therefor,'connections whereby a closed local circuit is established through the field and armature to produce a dynamic brakingrefiect and a high resistance connection established for energizing the field during braking to insure the rapid building up of the fiel said parallel connection an '6. In a system of motor control, the combination w1th, a series motor, of areversing controller therefor connections whereby a closed local circuit is established through the field and armature of said motor to produce a dynamic braking efi'ect when the controller is moved toward the reverse position and a high resistance connection established for energizing the field during braking to insure the rapid building up of the field.

7. In a system of motor control, the combination with a series motor, of areversing controller therefor, connections-whereby a closed local circuit is established through the armature and field of the motorwhen the controller is moved toward thereverse posi tion and the line connection maintained through ahigh resistance. 4

8. In a system of motor control, the combination with a dynamo-electric machine having an armature and series field, of reversible connections between said armature and field, an open-circuited connection in parallel with said armature and field, a controller therefor, and means for reversing bination with a dynamo-electric'machine having an armature and series field, of re.-

.90 said armature connections and closing the- Y clrcuit of said parallel connection when said versible connections between said armature and field, an o en-clrcuited connection in parallel with sald armature and field, a controller therefor, automatic means for revers- 1ng said armature connections and closing the circuit of said parallel. connection when.

said controller is moved to off osition and means for insurin the correct polarityof said field during bra ing operation.

' 1-0. In a system of motor control, the combination with a dynamo-electric 'machine havin an armature and. series field, of reversibIe connections between said armature and field, an open-circuited connection in parallel with said armature and field, a controller therefor, automatic means for revers- -ing said armature connections and closing the circuit of said parallel connection when said controller is moved to off position, and means for inserting a resistance between the source of electric supply and said field durin braking operation.

11. n a system of motor control, the combination with ya dynamo-electric machine havin an armature and series field, of reversib e connections between said armature and field, an open-circuited connection in parallel with said armature and field, .a controller therefor, interlocked means for reversing said armature connections, and interlocked means for closing the circuit of sistance between the source of electric sup ply and said field, both said means beingacinserting a re havin tuated when the controller is moved to ofi' position. 1 12. In a system of motor control, the combination with a dynamo-electric machine an armature and series field, of reversib e connections between said armature and field, an open-circuited connection in parallel with said armature and field, a controller therefor, electro-magnetic switches for reversing said armature connections, electromagnetic switches for closing the circuit of said parallel connection and inserting a resistance between the source of electric supply and said field, said switches being arranged to be actuated by said controller when moved to ofi position.

.713. In a system of motor control, the combination with a dynamo-electric machine having an armature and series field, of reversible connections between said armature and field, an ,open-circuit'ed connection in parallel with said armature and field, a controller therefor, electromagnetic contactors for reversing said armature connections arran ed to be directly actuated by said controller, relays adapted to actuate said contactors preparato to braking operation, I and a switch for c osing the circuit of said Earallel connection, said relays and switch eing arranged to be actuated by said controller when moved to ofi position.

14. In a system of motor control, the combination with a dynamo-electric machine having an armature and series field, of reversible connections between said armature and field, an open-circuited connection in parallel with said armature and field, a controller therefor, interlocked electromagnetic contactors for reversing said armature connections arranged to be directly actuated by said controller, electromagnetic relays adapted to actuate said contactors preparatory to' braking operation, and electromagnetic switches for closing the circuit of said parallel connection and inserting a resistance between the source of electric supply and said field, said relays and switches being ar-.

ranged to be actuated by said controller when moved to Fofl' positlon.

' 15. In a system of motor control, the combination with a dynamo-electric machine havin an armature and series field, of reversib e connections between said armature and field, an open-circuited connection in parallel with said armature and field, a controller therefor, accelerating electromagnetic contactors in the motor circuit arranged to be actuated by the .motor current, interlocked electromagnetic contactors for reversing said armature connections arran ed to be directly actuated b said contro er, electromagnetic relays a apted to actuate said contactors preparatory to braking 0 eration, and electromagnetic switches for 50s- .ing the circuit of said parallel connection and inserting a resistance between the source of electric supply and said field, said relays and switches being arranged to be actuated by said controller when moved to off position.

In witness whereof, I have hereunto set my hand this 2nd day of February, 1918.

BENJAMIN WALTON JONES. 

